November 17, 2015

Computer Code Takes Quantum Leap

Australian physicists have written the
purest “quantum” computer code yet, outpacing the speed of light and dispelling
doubts that quantum computers — fantastically powerful processors that leave
modern supercomputers for dead — may soon be a reality.

A University of NSW team claims to have notched
the latest milestone in what has been dubbed “the space race of the 21st
century”, with the most convincing evidence that quantum computer code is
feasible. And the team achieved the feat in silicon, the computing industry’s
material of choice.

“We have the operation of a quantum computer
entirely under control,” said team leader Andrea Morello, co-author of a report
in the journal Nature Nanotechnology. “We have shown beyond any doubt
that we can write this code inside a device that resembles the silicon
microchips (in) your laptop or mobile phone.”

While they are still at the theoretical stage,
quantum computers have massive potential in fields including drug design,
finance, security and biological modelling. They harness the weird quantum
properties of atomic particles — which can become “entangled” across vast
reaches of space, and exist in numerous locations and states simultaneously — to
perform calculations far beyond the reach of today’s most advanced
supercomputers.

While Albert Einstein famously disparaged
entanglement as “spooky action at a distance”, British physicist John Bell
devised a test to verify whether particles were entangled. For more than 50
years, the Bell test has functioned as the gatekeeper between classical and
quantum physics.

Four weeks ago, a Dutch team satisfied the Bell
test in demonstrating entanglement of atomic particles located 1.3 kilometres
apart. While the Australian researchers managed entanglement over an infinitely
shorter expanse — the distance between a phosphorus nucleus and its electron —
they believe they have achieved the highest ever score in a Bell
test.

They also managed this in the industrial friendly
medium of silicon. Rival teams around the world — some of which are backed by
information technology heavyweights like Google, Microsoft, IBM and Intel — are
developing quantum computers in vacuums, which would be extremely difficult to
scale up on a commercial scale.

Professor Morello said the latest experiments were
the “logical next step” after the team last month reported the design of a
three-dimensional silicon chip based on quantum bits — providing a blueprint for
large-scale quantum computers. He said every extra quantum bit effectively
doubled the number of codes that could be written, providing exponentially more
processing power than conventional computer bits. “At the level of two quantum
bits it doesn’t seem like much, but as you get to 10 or 20 or 50, it’s
enormous.”

Co-author Stephanie Simmons said this was the
secret behind quantum computers’ power. “(They) allow us to write a computer
code that contains many more words.”

Last month the OECD listed quantum computing —
along with big data and the “Internet of Things” — as the “new generation”
information technology trends laying the groundwork for profound transformations
to future life and work.